The invention discloses a power distribution network main transformer operation equalization optimization method, and relates to the field of power distribution of a power grid. At present, the problem that the utilization rate of power grid equipment in the existing power consumption valley period is intensified or the phenomena of low power grid construction investment return rate and power gridconstruction investment waste are caused while the problem of serious overload of the main transformer of the power distribution network is solved. According to the technical scheme, the method comprises the following steps: optimization target main transformer groups are screened; main transformer equalization optimization calculation is carried out on each target main transformer group by changing the combination mode of feeders accessed to the main transformers, and the comprehensive index of each candidate scheme is calculated; the candidate schemes are sorted according to the comprehensive index, and an optimal scheme is screened out for power flow calculation verification; and the feasibility of each candidate scheme is evaluated according to the network loss value, and an optimal feasible scheme is obtained to carry out actual transformation on the power distribution network. According to the technical scheme, the load peak values and volatility of the main transformers are reduced and the openable capacity of the main transformers of the power distribution network is improved by changing the feeders connected to the main transformers, and the method is of high operabilityand remarkable generalizability.